Scaffold-support.



J'. J. MAGKLEM.

SGAFFOLD SUPPORT.

APPLICATION FILED MAR. 10, 1914.

Patented Feb. 23, 1915.

WW I z A TTORNEY THE NORRIS PETERS CO., FHOTC-LITHO.. WASHINGTON. Dv C,

JOHN J. MACKLEM, OF HOQUIA1VI,.VTASI-IINGTON.

SGAFFOLD-SUPPORT.

Specification of Letters Patent.

Patented Feb. 23, 11915.

Application filed March 10, 1914. Serial No. 823,659.

To all whom it may concern:

Be it knownthat 1, JOHN J. MACKLEM, a citizen of the United States, residing at Hoquiam, in the county of Chehalis and State of Washington, have invented certain new and useful Improvements in Scaffold- Supports, of which the following is a specification.

This invention relates to extensible trestles for use by painters, carpenters and other artisans who work upon scaffolding.

-tion applied thereto.

The object of the invention is the perfecting of apparatus ofthis class to render the same more convenient to handle and ad just and obviating all danger of the apparatus collapsing through slipping of the parts where they are joined.

The invention consists in the novel construction and adaptation of devices, as will be hereinafter described and claimed.

In the accompanying drawings, Figure 1 is an elevational end view shown partly in section of a trestle with the present inven- Fig. 2 is a fragmen tary side view of the same to an enlarged scale. Fig. 3 is a detail sectional view through 3-3 of Fig. 1. Fig. 4 is a perspective view of a securing bolt and nut for fit) one of the trestle legs. Fig. 5 is a per? spective view of a trestle-leg bracket attachment. k

A trestle, as shown in Fig. 1, is formed substantially like the letter A being constituted of two oppositely inclined legs, each of which is comprised of an upper member 10 and a lower member 11. Said legs are connected near their top ends by a bolt 12 and at a distance therebelow by a transversely arranged bar 13 which is rigidly secured to the lower ends of the leg-members 10.

The members of eachleg are extensibly connected by means of a strap or plate 14 whichis rigidly secured to the bar 13 and an upper member 10 so as to provide with the latter a sleeve or housing (see F ig. 3) in which the lower member 11 is endwise slidable. To fasten the member 11 in adjusted position with respect to its companion member 10, I provide the following described devices: Each such fastening device comprises a pair of links 16 which are pivotally connected in proximity to their inner ends to a pin 17 which. is secured to and passes through a lower leg member 11. The

other ends of the referred to links are pivotpivotally connected the lower end of a bifurcated clamping plate 19. 20 represents a bolt which is screw-threaded at one end and is provided with a head 20 at the other end. Adjacent to the head the bolt is formed square in cross-section so that when the bolt is inserted in a correspondingly shaped hole 21 in the member 11, the bolt is rendered non-rotatable. The bolt thus secured to the lower member extends through a slot 10 provided in the upper member 10 and to a distance beyond the clamping plate 19. Provided for the bolt 20 is a winged nut 22 having in its periphery a groove 22 to receive the bifurcations 19 of the clamping plate thereby engaging the nut'to the latter for independent axial movements but allowing the nut being turned upon the bolt. To prevent the nut bearing against the adjacent leg-member, the plate 19 is curved to have its central portion whereon is carried the nut in spaced relation with the legmember 10 when the plate-ends are juxtaposed therewith.

In operating the above described fastening devices, a nut 22 is first unscrewed to re move the strain which is applied through the bolt 20 to the plate 19, which serves as a washer with respect to the nut. Upon the plate being thus loosened, the leg-member 11 is adjustably moved lengthwise with respect to the member 10, it being freely movable through the housing 14, and the bolt 20 is free to. move within the slot 10 When a leg is properly regulated, the securing bolt 20 therefor is caused to become operative through the agency of the nut 22 thereof in cooperation with the plate 19 so that the members of a leg will be clamped between a bolt-head and the plate. When the relative positions of the companion-members of a leg are changed, the links 16 will accommodate themselves to the relative movements of the members only when the nut is unscrewed, otherwise any tendency of the upper member to slip would be counteracted through the office of the links and the greater the load the more securely will the links cause the plate to engage the legmember.

It may be said that in practice the legmembers are constructed of wood and the tightening of the nut causes the ends of a plate 19 to embed themselves sufliciently into the material so that no appreciable movement will ensue between the plate and.

the leg against which the same bears when constrained by the bolt and nut.

Also included in the invention are devices ,which surmount the leg-members l0 and serve as jaw elements by which the trestle is gripped through the instrumentality of the aforesaid bolt 12 to a beam 24 whereby a platform board or boards, indicated by 25, are supported. Said jaw members are constructed of metal, such as malleable iron, and are-each comprised of a saddle-shaped block 26 which is fitted to the upper ends of the respective leg-member 10 and provided with holes to accommodate the bolt 12. The bolt 12 isprovided with a head at one end and the other end is screwthreaded to receive a winged nut 27 wherewith the beam 24 is clamped between said jaw-members.

The blocks 26 are each provided with an arm 28 to serve as a bracket-support for a board, as indicated by 29, which may advantageously be employed as a bridge between the two trestles similar to that illus trated in Fig. 1. To prevent any displacement of a board upon the bracket-support 28, the latter is formed on its top with projections 30 to penetrate the wood.

The operation of the invention will, it is thought, be understood from the foregoing.

What I claim, is

1. In apparatus of the class described, the combination with the leg-members, a plate seated against one of said members, link connections between the lower end of said plate and the member remote from the plate and means extending through both of the members and the plate whereby the members are clamped together.

2. In apparatus of the class described, the combination with a leg formed of two members extensibly connected together, of fastening means for securing said leg-members in adjusted positions, said means comprising a headed bolt extending through both members, a plate juxtaposed with one of said members, links pivotally connected with said, plate and also with the member remote therefrom, and anut engaging screw-threads of said bolt and arranged to engage against said plate whereby the legs are caused to be clamped between the plate and the head of the bolt.

3. In apparatus of the class described, a fastening means for securing an extensible leg in adjusted positions, said means comprising a screw-threaded bolt secured to one of said members and passing through a slot provided in the other of the leg-members, a plate connected with the first named member and juxtaposed with the other member, and a nut engaging with the bolt and cooperating with the latter and the plate for clamping the two members together.

Signed at I-Ioquiam, Wash, this 24th day of February, 1914..

JOHN J. MACKLEM. lVitnesses (ino. F. PALMER, C. J. RITCHIE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. C. 

